在二甲氨酸单离子中,键对称性
Charles L Perrin1, Phaneendrasai Karri, Curtis Moore
1Department of Chemistry, University of California-San Diego, La Jolla, California 92093-0358, USA. cperrin@ucsd.edu
Journal of the American Chemical Society
|April 24, 2012
概括
在水和有机溶剂中,二甲酸单离子体表现出分体形式,而不是单一的对称结构. 然而,在液晶中,它采用对称的键结构,受其环境的影响.
科学领域:
- 化学物理 化学物理
- 晶体学 晶体学是指结晶学.
- 频谱学是一种光谱学.
背景情况:
- 键在化学和生物学中至关重要.
- 了解键对称是分子相互作用的关键.
- 二甲单离子是研究键动态的一个模型系统.
研究的目的:
- 为了研究二甲酸单离子中键的对称性.
- 为了确定monoanion是否存在于单个对称结构或平衡 tautomers.
- 探索当地环境对键对称性的影响.
主要方法:
- 使用X射线结晶学来确定晶体结构.
- 使用核磁共振 (NMR) 光谱与同位素扰动 (使用氧-18) 被使用.
- 研究是在水,近极有机溶剂 (CD(2) Cl(2),CD(3) CN) 和同位素液晶中进行的.
主要成果:
- 射线晶体学揭示了一个对称的键,具有短的O-O和相同的O-H距离 (分别为2.41 Å和1.206 Å).
- 核磁共振同位素扰动显示水和有机溶剂中的非等效,表明分体形式.
- 在液晶阶段,NMR显示相当于,表明对称结构.
结论:
- 二甲烯酸单离子存在于水和有机溶剂中的平衡分离体中.
- 在同位素液晶环境中观察到单一对称的键结构.
- 当地环境对键的对称性有很大的影响.
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